Why a Peach Sent Me to the Emergency Room

One of the joys of summer is the delicious produce, and where I’m from—rural Pennsylvania—it’s plentiful. But one evening a decade ago, a summer peach landed me in the hospital.

Ever since early childhood, a ripe plum, apple, or another select fruit would sometimes create a series of hives on my lips and cause a tickly sensation in the back of my throat. These were fleeting and seemingly harmless episodes (usually cured by some antihistamines), and neither I nor my parents ever heard of this type of reaction in others. Nor did we know why it happened. I already had seasonal allergies and thought this might be some quirky kind of food allergy—but had never treated it as a serious threat.

As I ate my peach that night, I noticed the same symptoms I always did. But this time, the sensation didn’t go away, even with the assistance of an antihistamine. As my throat began to close and my breathing became restricted, I realized this was probably a more serious case of anaphylaxis. Off to the ER I went, where a shot of epinephrine calmed my symptoms. It was a close call from such an unassuming fruit.

Only later – after reading, guess what, a blog – did I discover my ordeal had a name: Oral Allergy Syndrome (OAS). OAS affects anywhere from one to two thirds of seasonal allergy sufferers – although most, like me, are not aware of it. As an OAS sufferer, my too-smart-for-its-own-good immune system notices that the proteins of fruits like apples and kiwis are chemically similar to the proteins of pollens of things like birch trees and ragweed, which it has already targeted for attack. The fruit is then treated as an allergen: an invader that must be destroyed. An antibody called immunoglobulin E (IgE) picks a fight with the protein, releasing chemicals like histamine and creating inflammation and irritation. In the case of OAS this mix-up – or cross reaction, as it’s called – is localized in and around the mouth.

Peaches, apparently, cross-react with the pollens of birch trees and grasses. So as someone with both of those allergies, my reaction that night makes sense. I was also particularly at risk that year because of the high summertime pollen levels that already were pushing my immune system into overdrive. This summer – following what has been deemed the worst allergy season ever – you can be sure I’ll be keeping my eye on the seemingly sweet and innocent fruit bowl.